Missing .so files for running

[ardunn]

This version of combo does not currently have the following cythonized files to run COMBO.
in combo/combo/gp/_src:

enhance_gauss.so

in combo/combo/misc/_src:

cholupdate.so
diagAB.so
logsumexp.so
traceAB.so

These files can be easily generated via cython but the current version of combo will throw an ImportError because it cannot find them, as only the .pyx and .c files are currently included.